The present invention relates to a computer and a method for controlling a cooling fan in a computer, and in particular, to the control of a cooling fan in a computer which can connect to an external device in an expansion unit.
An expansion unit to expand functions of a notebook personal computer (PC), for example, a docking station, has a cooling fan for cooling a device and power supply mounted in the docking station.
Conventionally, this cooling fan is controlled on the basis of temperature inside a power supply detected by a temperature sensor provided inside the power supply. For example, control is performed so that the cooling fan is operated and the inside of the docking station is cooled if detected temperature is higher than predetermined temperature, and that the cooling fan is stopped if the detected temperature is equal to or lower than the predetermined temperature.
However, there is not certain correlation between the temperature inside the power supply and the temperature of a device requiring the cooling by the cooling fan, and only the temperature inside the power supply is measured, and hence there is a case that it is not possible to surely actuate the cooling fan when the temperature of the device is high.
Furthermore, since various devices are mounted in the expansion unit such as the docking station, it is not possible to know beforehand which portion is easy to be heated, and it is difficult to provide a temperature sensor beforehand at a portion where temperature is easy to rise.
By the way, recently, a standard called ACPI (Advanced Configuration and Power Interface) which allows power supply management to be performed predominantly by an operating system is well known as power management (power supply management) for a PC.
In addition, according to the PC 99 design guide which is a hardware specification of a computer laid down by Microsoft Corporation, under the above-described ACPI environment, a behavior of a PC should look the same in a sleep mode and in a power-off state for a user.
Thus, in case of the above-described cooling fan, for example, since the cooling fan stops and does not generate noise at the time of the power-off state, the cooling fan must be also stopped for preventing the noise from being generated in the sleep mode.
However, in order to stop the cooling fan also in the sleep mode, a temperature condition for actuating the cooling fan must be set higher than normal to prevent the cooling fan from being accidentally operated in the sleep mode.
Thus, the cooling fan may not operate even when the PC operates normally, and hence there is a problem that the cooling fan cannot sufficiently cool a device that is mounted in the docking station.
The present invention is provided in consideration of the above-described facts, and an object of the present invention is to provide a computer, which can adequately control the cooling fan to cool the device mounted in the expansion unit, and a method for controlling the cooling fan.
In order to achieve above-described objects, a computer according to the present invention can connect to at least one external device, which operates by, for example, a clock being supplied at least from the external thereto. Such external devices include, for example, a storage device such as a hard disk, a PC card, a CD-ROM drive, a DVD-ROM drive, and the like, and operated by electric power and clock being supplied from the external thereto.
These external devices are used, for example, by being connected with a computer main body and can be mounted in an expansion unit for expanding functions, and an expansion slot provided in the computer main body. In addition, the computer main body or expansion unit has a cooling fan for cooling a power supply device, which supplies electric power to an external device and the above-described external device.
In such a computer, detection means detects the supply of a clock to the external device. Thus, the detection means detects whether the clock is supplied to the external device and the external device is under operation. Here, the state in which the clock is not supplied is, for example, a case that the computer is in the sleep mode.
Signal output means outputs an actuation signal to actuation means for actuating the cooling fan, on the basis of the clock. For example, when the clock is detected, namely, when it is detected that the clock is supplied to the external device and the computer is in an operating state, the signal output means outputs the actuation signal for actuating the cooling fan, to the actuation means. The actuation means is composed of, for example, a switching device such as a MOS-FET, and drives the cooling fan with the actuation signal. In addition, when the clock is not detected, namely, for example, when the computer is in the sleep mode, the supply of the clock to the external device is stopped, and when the external device is in a non-operating state, the signal output means outputs a stop signal for stopping the cooling fan, to the actuation means. Owing to this, the cooling fan is stopped.
In this manner, since the actuation/non-actuation of the cooling fan is controlled by whether the clock is supplied to the external device, it is possible to surely actuate the cooling fan when the external device operates, and hence it is possible to fully cool the external device.
In addition, it is possible to make the detection means include integration means, integrating the clock signal, in an input stage. Owing to this, the signal output means can output a signal at a fixed level while the clock signal is inputted and can make this as an actuation signal. In this manner, it is possible to actuate the cooling fan in simple configuration.
Additionally, if the temperature inside the computer is still high like just after shifting from a normal operation mode to a sleep mode even if the clock is not supplied to the external device, it is preferable to perform cooling by the cooling fan.
Then, it can be performed that the computer further includes at least one temperature sensor detecting the temperature inside the computer, and the signal output means outputs the actuation signal to the actuation means on the basis of the clock and detected temperature by the temperature sensor.
For example, if the clock is not detected and the detected temperature by the at least one temperature sensor is equal to or higher than a predetermined value, that is, as described above, if the temperature of the external device and power supply device is still high just after shifting from the normal operation mode to the sleep mode, the actuation signal is outputted to the actuation means.
Owing to this, if the temperature inside the computer is still high even if the clock is not supplied to the external device, it is possible to perform cooling by the cooling fan, and hence it is possible to cool the inside of the computer more immediately. In addition, one or plural temperature sensors can be provided.
In a method for controlling a cooling fan in a computer that can connect to an external device and has a cooling fan for cooling the external device, the method for controlling the cooling fan according to the present invention comprises the steps of: detecting the supply of a clock from the computer to the external device; and actuating the cooling fan on the basis of the clock.
Owing to this, it is possible to surely actuate the cooling fan when the external device operates, and hence it is possible to fully cool the external device.
In addition, it can be also performed to actuate the cooling fan on the basis of the clock and detected temperature by the temperature sensor by further detecting the internal temperature of the computer.
Owing to this, if the temperature inside the computer is still high even if the clock is not supplied to the external device, it is possible to perform cooling by the cooling fan, and hence it is possible to cool the inside of the computer more immediately.